Ddx23, also known as PRP28, is a spliceosomal RNA helicase involved in pre-mRNA splicing [1]. It is part of the spliceosomal complex, and its ATPase activity is crucial for the pre-B to B spliceosome complex transition and for the release of U1 snRNP from the 5' splice site [1]. Besides RNA processing, mammalian Ddx23 is also implicated in antiviral responses, suggesting its importance in multiple biological pathways [2,3].

In fish, knockdown of black carp Ddx23 (bcDDX23) enhanced host cells' resistance against SVCV, indicating bcDDX23 negatively regulates MAVS-mediated antiviral signaling [2]. In human cells, knockdown of DDX23 enhanced VSV replication and reduced NF-κB and IRF3 activation, and DDX23 translocated to the cytoplasm to form complexes with TRIF or MAVS upon stimulation [3]. In ovarian cancer, silencing DDX23 impeded cell proliferation/invasion in vitro and tumor growth in vivo, as it regulated FOXM1 mRNA processing [4]. Also, in non-small-cell lung cancers, DDX23 can bind to the promoter of linc00630 to up-regulate its RNA level, forming an axis with linc00630-HDAC1 to promote metastasis [5].

In conclusion, Ddx23 is essential for pre-mRNA splicing and has significant roles in antiviral immunity and cancer progression. Functional studies, especially those using knockdown models, have revealed its importance in these biological processes and disease conditions, providing insights into potential therapeutic targets for viral diseases and certain cancers.